Analysis of Interdiffused InGaN Quantum Wells for Visible Light-Emitting Diodes

Interdiffused InGaN quantum wells (QWs) with various interdiffusion lengths (L_d) are comprehensively studied as the improved active region for Light-Emitting Diodes (LEDs) emitting in the blue and green spectral regime. The electron-hole wavefunction overlap (Γ_{e_hh}), spontaneous emission spectra, and spontaneous emission radiative recombination rate (R_sp) for the interdiffused InGaN QWs are calculated and compared to that of the conventional InGaN QWs emitting in the similar wavelengths. The calculations of band structure, confined energy levels, electron and hole wavefunctions, and spontaneous emission radiative recombination rate (R_sp) are based on the self-consistent 6-band k·p method, taking into account the valence band mixing, strain effect, spontaneous and piezoelectric polarizations and carrier screening effect. Studies indicate a significant enhancement of the electron-hole wavefunction overlap (Γ_{e_hh}) and the spontaneous emission radiative recombination rate (R_sp) for the interdiffused InGaN QWs. The improved performance for the interdiffused InGaN QWs is due to the modification of the band lineups at the InGaN-GaN interfaces, which leads to the enhancement of the electron-hole wavefunction overlap significantly.